Electric switch



A. c. PREscoTT 2,480,161

ELECTRIC SWITCH 2 Sheets-Sheet l mgl.

Aug. 30, W49.

Filed June 14, 1945 Inventor: Yfnwbhm 0.10 escott,

y/ i5 Attorney.

A118- 30 l949- A. c. PRI-:sczoTTA 2,480,161

ELECTRIC SWITCH Filed June 14. 1945 2 Sheets-Sheet 2 lllllllllllill Ihvenbor 2 Arthur C. prescotb,

Patented Aug. 30, 1949 ELECTRIC swrrcn Arthur C. Prescott, Schenectady, N. Y., assigner. v.

to General Electric Company, a corporation o! New York Application June 14, 1945, Serial No. 599,398

(CI. 20o-87) 4 Claims. l

My invention relates to electric switches, more particularly to shockproof electromagnetically operated switches of the type known as contactors, and has for its object a simple, reliable and shockproof electric switch.

In carrying out my invention in one form, I provide operating mechanism for the movable switch contacts comprising a contact supporting member mounted for substantially straight line movement, together with an eccentric connected to .move the contact supporting member, and a rack for operating the eccentric connected through a lever to the operating magnet.

For a more complete understanding of my invention, reference should be had to the accompanying drawing, Fig. l of which is a side elevation view, partly in section, of an electric switch embodying my invention; Fig. 2 is a iront elevation view with parts broken away of the device shown in Fig. l; while Fig. 3 is a sectional view of part of the operating mechanism taken along the line 3--3 of Fig. 2 looking in the direction of the arrows.

Referring to the drawing, in one form of my invention I provide a supporting member I shown as a channel iron on which is mounted on its central or base portion a U-shaped metal bracket 2 having the outer ends 3 and 4 of its sides bent toward each other into parallel relation with the support I. On the ends 3 and 4 is mounted a stationary contact supporting plate 5 by means of suitable bolts only two of which, 6 and 1, are shown, this plate being made of electrically insulating material and provided with a plurality of central apertures 8 through each of which extends a switch operating bar or rod 9 bearing on its outer end the movable contacts I and II. The movable contacts are arranged to cooperate with stationary contacts I2 and I3, each of which is mounted on an electrically conducting strap member I4 electrically secured, in turn, by bolts I and I6 to a terminal connector strap I1. An additional insulating spacing inember Il is provided between each terminal connector I'I and the plate 5, this insulating ni'ember Il having barrier walls I1a forming a recess for its particular terminal strap and contact support I4 and these parts being secured together and to the plate 5 by the bolts I 5 and I5. A cover I9 made of molded electrically insulating material encloses the movable contacts and is secured in place tightly on the member I3 by bolts 2l and 2| at its ends threaded into the terminal stra-p I1. y

It will' be seen that, in the particular device 2 disclosed, three poles or circuits are provided, each duplicating the one just described and each provided with a separate cover. Such a switch would be used, for example, in a three-phase circuit.

Each of the three operating bars or rods 9 is secured to a transversely extending bar 22 made of electrically insulating material positioned on the left hand side of the supporting plate 5, as seen in Fig. 1. At its opposite ends, this bar is pivotally secured by links 23 and 24 (Fig. 2) to the opposite ends of a bar 24' in turn secured to the U-shaped support 2 and extending in parallel relation with the support I. The two links 23 and 24 are rigidly secured together by a cross bar 23' so that the two links move together.

For the purpose of moving the support 22 on the links 23 and 24, an eccentric 25 is provided (Fig. 3) rigidly secured to one end of the shaft 23 journalled in a supporting block 21, which in turn is secured to the bracket 2 as by welding. A connection is provided between the eccentric 25 and the bar 22 by a movable bracket member 23 having an aperture 29 (Fig. 1) in which the eccentric 25 fits loosely, this aperture being elongated in a direction parallel with the support i to provide for lateral movement of the eccentric as it is turned by the shaft 26. A transversely extending portion on the bracket 28 is secured to the left-hand sidev of the cross bar 22, as seen in Fig. 1. Also, the bracket 28 is pivotally connected by means of a link 3| (Fig. 2) to a projection 32 secured to the U-shaped bracket 2. This link 3I is parallel with the links 23 and 24, but as shown it is somewhat shorter, the links supporting the bar 22 and the movable contacts for movement in a substantially straight line.

For turning the shaft 2B and the eccentric 25, a spur gear 33 is provided on the opposite end of the shaft which meshes with a rack 34 .mounted for slidable movement on the support I. For the purpose of providing a substantially friction-free support for the rack 34, two rollers 35 and 35 are provided which are secured to a support 35', the support 35' being secured to the bracket 2 by bolts 3i as shown in Fig. 1. 'I'he rollers 35 and 36 extend into a longitudinal groove 31 on the rearward side of the rack 34 whereby'the rack is supported on the rollers. The opposite side of the rack has one end in engagement with a flat guide 33 secured to the bracket 2 and its other engaging a lever 40 and whereby the rack is held against the rollers 35 and 35 a counterweight member It is secured to-the rack and extends under the guide 3l.

encoder In turn, the rack is moved up and down by means of a lever 40 mounted on a pivot post di secured to the bracket 2 between the base portion and the end portion t, the lever extending in parallel relation with the base of the bracket 2. One end of the lever is provided with a slot 42 into which extends a pin 6c secured to the rack and provided with a partly spherical bearing surface loosely engaging the sides of the slot 42. The opposite end o the lever is connected through a similar pin and slot connection to the armature 44 of a magnet l5 A helical spring d@ has its lower end attached to the lever fi@ and its upper end secured to the support 2 so as to apply a counterclockwise force to the lever QQ, as seen in Fig. 2, and thereby bias the switch in its open circuit position shown.

Upon energization ci the magnet d5, the armature 4d is pulled downward whereby the-rack 3G is moved upward, as seen in the drawing, and the eccentric turned to move the cross bar 22 toward the left hand, as seen in Fig. l, whereby the mov the stationary contacts for closure of the switch. Preferably. the eccentric is in one dead center position when the switch is open, as shown in Fig. l, and it is moved to its opposite dead center position for closure of the switch. Thus the movable switch member is secured by the eccentric in each position against movement as the result of a shock.

Each pair of movable contacts i@ and ii are electrically connected to each other by means of a flexible electric conductor di so that the two I together form a bridging contact. By means of a leaf spring 48 connected to the two contacts, the contacts are biased toward their closed cir cuit position, the spring 48 bending upon engagement of the contacts to provide a desired amount of sliding and wiping action between the contacts. As shown, thel middle of the springl engages a bar 49 whose opposite ends extend through elongated slots in contact supporting members 50 and 5I. Preferably the spring 48 is stressed somewhat by the bar 49 when the contacts are disengaged thereby to provide an initial pressure at the instant of engagement of the contacts.

An additional shockproof feature is balancing of the weights of rack 34 and the armature 44 together with the lever 40 about the axis of the pivot part 4I. In other words, the rack 34 serves both as a driving member and as a counterbalancing member for the armature 44, the weight 39 on the rack being provided for balancing purposes. In other words, the movable parts not driven by the eccentric are counterbalanced.

A stop projection 52 is provided on the lever 40, which stop 52 engages the lower resilient side arm of the bracket 2, as shown in Figs. 1 and 2, when the switch is open. This side arm is constructed to have a very substantial resiliency under shock conditions so that it absorbs a sub-` stantial amount of the shock force and prevents the transmission of suiiicient shock force to the moving parts to cause false operation and closure of the switch by the shock. I refer to high 1mpact shocks up to 2000 foot pounds.

Arc extinguisher plates 53 made of a magnetic material such as steel are provided at opposite ends of each cover I9 opposite the pairs of contacts. These plates have their outside edges and ends embedded in the end and side walls of the cover.

While I have shown a particular embodiment able contacts are moved into engagement with of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modigcations may be made, and i therefore contemplate by the appended claims to cover any such modifications es fall within the true spirit and scope of my invention.

What l'. claim as new and desire to secure by Letters Patent of the United States is:

l. An electromagnetically operated switch coing prising a slidably mounted rack, an operating coil, an armature for said coil, a lever connecting said armature to said rack for slidably moving said raci; between two positions, the weights of said armature, lever and rack being balanced about the pivot oi said lever, a pinion meshing with said rack, an eccentric operated by said pinion from one dead center position to another, a switch member moved by said eccentric between two circuit controlling positions each corresponding to one of said dead center positions, supporting means for said switch member for giving said switch member a substantially straight-line movement, a movable switch contact mounted on said switch member. and a cooperating stationary contact mounted on said support. r

2. An electromagnetically operated switch com prising a slidably movable rack, an operating coil, a movable armature for saidl coil, a lever movable about its pivot connecting said armature to said rack for slic'iable movement o said reci: between two positions, the weights of said movable parts being balanced about the pivot of said lever, a pinion meshing with said rack. an eccentric operated by said pinion from one dead center position to the other, a switch member connected for movement by said eccentric between two circuit-controlling positions each correspond' ing to one of said dead center positions, supporting means for said switch member for giving said switch member a straight-line movement a movable switch contact mounted on said switch member, a cooperating stationary switch contact mounted on said support, and a resilient stop engaged by one of said movable parts in its open circuit position for preventing shock movement of said parts to their closed circuit positions.

3. An electromagnetically operated switch com' prising a rack, an operating coil, an armature for said coil, a lever connecting said armature to said rack for slidably moving said rack between two positions, the weights of said armature, lever and rackbeing balanced about the pivot of said lever, a pinion meshing with said rack, an eccentric operated by said pinion from one dead center position to the other. a switch member connected for movement by said eccentric, in a direction substantially perpendicular to the direction of movement of said rack and between two circuit controlling positions each corresponding to one of said de'ad center positions, supporting means for said switch member for giving said switch member a straight-line movement, a movable switch contact mounted on said switch member, a cooperating stationary switch contact mounted on said support. and a resilient stop engaged by said lever in its open circuit position for preventing shock movement of said lever to its closed circuit position.

4. A switch comprising a ilrst support, a metal mounted on opposite sides of said aperture on the outer side of said second support. a movable switch operating member extending through said aperture, a pair of spaced apart parallel links connecting said operating member to said bracket for substantially straight-line movement through said aperture, a bridging contact member mounted on the outer end of said operating member cooperating with said pair of stationary contacts, a rack mounted for slidable movement on said rst support in a direction substantially perpendicular to the direction of movement of said switch operating member, a pinion meshing with said rack, an eccentric operated by said pinion, an operating connection between said eccentric and the inner end of said operating member for moving said operating member and.

said bridging contact member into and out of engagement with said stationary contacts when said eccentric is turned from one dead center position to the other with respect to said operating member, and operating means on said rst support including a balanced lever connected t said rack for rotating said pinion and said eccentric from a first of said dead center positions to the other, and spring means connected to said rack for biasing said rack to a position in which said eccentric is in its said rst dead center position.

. ARTHUR C. PRESCO'IT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 698,096 Ball Apr. 22, 1902 994,212 Sundh June 6, 1911 998,786 Loeier July 25, 1911 1,016,329 Jones Feb. 6, 1912 1,364,908 Werner Jan. 11, 1921 1,783,784 Grcndahi et a1.' Dec. 2, 1930 1,965,125 Ketay July 3, 1934 2,086,628 Matejka July 13, 1937 2,240,007 Power Apr. 29, 1941 2,266,536 Cooper Dec. 16, 1941 2,283,795 Dahl May 19, 1942 2,432,782 McClain Dec. 16, 1947 

